Climate change and global issues in allergy and immunology

The steady increase in global temperatures, resulting from the combustion of fossil fuels and the accumulation of greenhouse gases (GHGs), continues to destabilize all ecosystems worldwide. Although annual emissions must be halved by 2030 and reach net zero by 2050 to limit some of the most catastrophic impacts associated with a warming planet, the world's efforts to curb GHG emissions fall short of the commitments made in the 2015 Paris Agreement. To this effect, July 2021 was recently declared the hottest month ever recorded in 142 years. The ramifications of these changes for global temperatures are complex and further promote outdoor air pollution, pollen exposure, and extreme weather events. Besides worsening respiratory health, air pollution promotes atopy and susceptibility to infections. The effects of GHGs on pollen affect the frequency and severity of asthma and allergic rhinitis. Changes in temperature, air pollution, and extreme weather events exert adverse multisystemic health effects and disproportionally affect disadvantaged and vulnerable populations. This review article is an update for allergists and immunologists about the health impacts of climate change that are already evident in our daily practices. It is also a call to action and advocacy, including to integrate climate change-related mitigation, education, and adaptation measures to protect our patients and avert further injury to our planet. (J Allergy Clin Immunol 2021;148:1366-77.)